In this section, we will briefly introduce the different definitions of Fairness that we will consider in this paper. In particular, we will concentrate on statistical – or global – notions of Fairness that are the most popular among ML practitioners. There exist other definitions based on causal mechanisms that provide a local measure of discrimination [1]} or [2]} – and that play an important role in social applications, where discrimination can be assessed individually –, but they are beyond the scope of this paper.
